The present invention belongs to a class of mounting clips that are useful in the construction of buildings, particularly commercial buildings where a non-load bearing, exterior curtain wall is connected to the load bearing elements of a building and the curtain wall needs to be able to move with respect to the load bearing elements.
It is often advantageous to attach curtain walls systems to the load bearing elements of a building with connectors that permit a degree of relative movement between the wall system and other components of the building. There are many reasons for this. For example there can be extreme differences in temperature between the exterior curtain walls and the interior load bearing systems, and because the exterior curtain wall and the load bearing system often have different coefficients of expansion based on their different materials, under extreme temperature differences the curtain wall wants to shift with respect to the load bearing system. Exterior walls of buildings are also subject to deflection from wind and seismic forces. Furthermore, curtain walls are typically not designed to support the vertical loads in the structure and must therefore by isolated from deflection of the primary load-bearing support structure of the building due to changes in live or dead loads carried by that structure. Providing a degree of freedom of movement within the wall and between the wall and the other components of a building can reduce stress and prevent fracture of connected parts due to the loading of the building, seismic and wind events, or differences in the temperatures of the curtain wall and the load bearing elements.
A number of clips that permit relative movement between structural members have been patented.
U.S. Pat. No. 5,467,566, issued in 1995 to Allan J. Swartz and Gregory A. Kulpa teaches a mounting clip that uses a fastener with a washer or spacer to allow for relative movement. The mounting clip is connected to the supported member and to the fastener with the washer in such a manner that the mounting clip can move with respect to the supported member. To allow relative movement between the fastener and the mounting clip, Swartz and Kulpa taught that the spacer or washer on the fastener should be received in slots in the portion of the mounting clip lying against the supported member and the spacer or washer should be thicker than the receiving portion of the mounting clip. Planar flaps or extensions which were part of the washer or spacer and disposed parallel to the receiving portion of the mounting clip extend over the receiving portion of the mounting clip and prevent it from pulling away.
U.S. Pat. No. 5,876,006, issued in 1999 to Terry L. Sharp and Richard C. Eldenburg also teaches a mounting clip where a spacer or fixed bracket is connected to the supported member and the mounting clip is attached to the supporting member and the fixed bracket in such a manner that the mounting clip can move with respect to the supported member. Like Swartz and Kulpa, to allow relative movement between the fixed bracket and the mounting clip, Sharp and Eldenburg taught that the fixed bracket should have an engaging component received by the portion of the mounting clip lying against the supported member that is thicker than the receiving portion of the mounting clip. Also, like Swartz and Kulpa, they taught that a planar securing component which is attached to the engaging component should extend in parallel relation over the receiving portion of the mounting clip. In Sharp and Eldenburg, their spacer or fixed bracket was a plate having a thickness that was greater than the portion of the mounting clip that received it, thus the securing component that projected outwardly from the top of the engaging component would not interfere with the movement of the mounting clip in the plane of the supporting member but keep it from pulling away.
Patents with similar teachings include U.S. Pat. No. 6,213,679, issued in 2001 to Frobosilo and Viola, and U.S. Pat. No. 5,906,080, issued in 1999 to diGirolamo and Mountcastle. U.S. Pat. No. 7,104,024, which issued in 2006 to diGirolamo et al, teaches having the spacers that allow for sliding motion of the mounting clip to also be connected to a u-shaped, reinforcing member that adds strength and rigidity to the connection.
The mounting clip of the present invention provides a uniquely shaped clip and slider that help to prevent the mounting clip from buckling under load.